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%I A020196 #23 Jun 25 2018 03:47:48
%S A020196 25,49,69,91,125,133,185,201,217,247,325,345,361,403,469,481,589,637,
%T A020196 805,871,925,931,1005,1025,1221,1225,1273,1417,1519,1541,1725,1729,
%U A020196 1771,1813,2077,2185,2211,2413,2527,2553,2665,2725,2821,3283,3325,3565,4033,4123
%N A020196 Pseudoprimes to base 68.
%C A020196 Composite numbers n such that 68^(n-1) == 1 (mod n). - _Michel Lagneau_, Feb 18 2012
%H A020196 T. D. Noe, <a href="/A020196/b020196.txt">Table of n, a(n) for n = 1..1000</a>
%H A020196 <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>
%t A020196 max = 5000; Select[Complement[Range[max], Prime[Range[PrimePi[max]]]], PowerMod[68, # - 1, #] == 1 &] (* _Alonso del Arte_, Jun 17 2018 *)
%Y A020196 Cf. A001567 (pseudoprimes to base 2).
%K A020196 nonn
%O A020196 1,1
%A A020196 _David W. Wilson_

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